The present invention relates generally to fluid heaters, and more particularly to an apparatus for heating a fluid such as ultra-pure de-ionized (UPDI) water.
Heated UPDI water is used in the manufacture of semiconductor devices. However, UPDI water is a corrosive liquid. Thus, equipment used for heating UPDI water must be capable of withstanding the corrosive effects of the UPDI water that flows therethrough.
In addition, it is critical that the equipment used to manufacture semiconductor devices be capable of performing specific tasks while not introducing contaminates into the manufacturing process. Until very recently, cost was not a primary concern for semiconductor manufacturing equipment, performing the task effectively was. With the semiconductor industry maturing, and competition increasing, performance and economy have both become important concerns.
In the area of fluid heating systems for use in the semiconductor manufacturing industry, the material most commonly used for resisting the corrosive effects of UPDI water has been Teflon, due to its relative ease of manufacture. Teflon adds virtually no contaminates to the process, however, it does allow for permeation of particulates, and biological growth, commonly referred to as total organic carbons (TOC's). Due to this problem, other materials have been studied, more specifically quartz.
Quartz has been used extensively for constructing process equipment in the semiconductor industry from the very beginning. Quartz is chemically resistant to most of the process fluids used, and also adds very little contamination. Although quartz has been used for tanks, furnace tubes, labware, and plumbing components, quartz has only recently been applied to UPDI water heating systems. Conventional quartz UPDI water heating systems, although very clean, and responsive to temperature/flow demand changes, are generally unreliable, inefficient, and very expensive to manufacture as well as to operate.
In particular, conventional quartz UPDI water heaters utilize standard quartz halogen radiant bulbs as a heat source. This approach permits fast response due to the low mass of the heating element, but has proven to be both unreliable, as well as inefficient. Known quartz UPDI water heaters typically achieve efficiencies in the mid 80% range.
Another problem with known quartz UPDI water heaters is that they tend to develop fluid leaks, and must be continually serviced. That is, forming reliable fluid-tight seals between the quartz components and the plastic components of the known quartz UPDI water heaters has been a problem for manufactures.
Accordingly, it has been considered desirable to develop a new and improved high-efficiency ultra-pure de-ionized fluid heater which meets the above-stated needs and overcomes the foregoing difficulties and others while providing better and more advantageous results.